"Childhood apple" in Engpsh is a phrase that refers to an apple that a person ate during their childhood. It is not a commonly used phrase in Engpsh, and there is no specific origin for it.

Here are a few examples of how you can use the phrase "childhood apple" in Engpsh sentences:

"I will always remember the taste of my childhood apple, it was so sweet and juicy." (我永远不会忘记我童年时吃的苹果的味道，它太甜太多汁了。)
"Eating a childhood apple brings back so many memories for me." (吃一个童年时的苹果让我回忆起许多记忆。)
"The smell of a childhood apple always reminds me of my grandmother's garden." (童年时的苹果的气味总是让我想起我祖母的花园。)